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INTEGRATED CIRCUITS
DATA SH EET
For a complete data sheet, please also download:
•The IC04 LOCMOS HE4000B Logic
Family Specifications HEF, HEC
•The IC04 LOCMOS HE4000B Logic
Package Outlines/Information HEF, HEC
HEF4557B
LSI
1-to-64 bit variable length shift
register
Product specification
File under Integrated Circuits, IC04
January 1995
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Philips Semiconductors Product specification
1-to-64 bit variable length shift register
DESCRIPTION
The HEF4557B is a static clocked serial shift register
whose length may be programmed to be any number of
bits between 1 and 64. The number of bits selected is
equal to the sum of the subscripts of the enabled length
control inputs (L1, L2, L4, L8, L16and L32) plus one. Serial
data may be selected from the DAor DBdata inputs with
the A/B select input. This feature is useful for recirculation
HEF4557B
LSI
purposes. Information on D
register position and all the data in the register is shifted
one position to the right on the LOW to HIGH transition of
CP0while CP1is LOW or on the HIGH to LOW transition
of CP1while CP0is HIGH. A HIGH on master reset (MR)
resets the register and forces O to LOW and O to HIGH,
independent of the other inputs.
or DBis shifted into the first
A
PINNING
D
, D
A
B
A/
B select data input
CP
0
CP
1
data inputs
clock input
clock enable input
MR asynchronous master reset
L
to L
1
32
O,
O buffered outputs
bit-length control inputs
Fig.1 Functional diagram.
HEF4557BP(N): 16-lead DIL; plastic
(SOT38-1)
HEF4557BD(F): 16-lead DIL; ceramic (cerdip)
(SOT74)
HEF4557BT(D): 16-lead SO; plastic
(SOT109-1)
( ): Package Designator North America
FAMILY DATA, IDDLIMITS category LSI
See Family Specifications
Fig.2 Pinning diagram.
January 1995 2
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January 1995 3
Philips Semiconductors Product specification
1-to-64 bit variable length shift register
Fig.3 Logic diagram.
HEF4557B
LSI